Análisis estadístico de la calidad en los procesos de inyección de plástico de la empresa Ecuatoriana de Matricería Ecuamatriz Cía. Ltda.

Abstract

The suboptimal quality control in the plastic injection process engenders a 3% loss due to defects such as incomplete, marbled, and deformed parts at ECUAMATRIZ Cía. Ltda. This directly translates into diminished product reliability and potentially dissatisfied clientele. To address this impact, a statistical analysis of quality in this process was developed. A quantitative and descriptive approach based on Six Sigma and DMAIC (Define, Measure, Analyze, Improve, and Control) was employed. For definition, data was collected through records and Pareto diagrams. For measurement, 100% sampling, R&R studies, and control charts were utilized. The analysis identified root causes using Ishikawa diagrams and the 5 Whys method. For improvement and control, the FMEA matrix was implemented, determining the most significant root cause and developing proposals with experienced personnel. The analysis of P control charts for attributes revealed unstable processes for marbling (5.5%), incomplete parts (0%), and deformation (2.7%), with sigma levels of 1.99, 2.06, and 2.64 respectively, evidencing deficient statistical control and high variability. The root causes were identified as lack of preventive maintenance, absence of records and control of critical parameters (temperature, pressure, injection speed, among others), lack of cleaning procedures, and insufficient personnel training. It was concluded that the plastic injection process exhibits a low level of quality and control, operating below globally required standards, representing an annual loss of 1.98% in terms of defects, reprocessing, and waste.